240 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 24 



curved fixed spines, the distal two very close together, and with a small, 

 proximal, outcurving spine. 



Material examined: Bahia de Tepoca, Sonora, Gulf of California, 

 11-13 fathoms; February 4, 1940; Velero III station 1078-40; one 

 male, one ovigerous female. 



West of Isla Coronados, Gulf of California, 3-10 fathoms; February 

 28, 1936; Velero III station 525-36; two males, two females (one 

 ovigerous). 



Off Isla Ceralvo, Gulf of California, 24° 12' N x 190°55' W, 9.5 

 fathoms; April 30, 1888; Albatross station 2826; one female (U. S. 

 National Museum Cat. No. 57657). 



[Puerto Escondido, Gulf of California, 18-21 fathoms; February 11, 

 1940; Velero III station 1096-40; 1 young. This specimen, which is only 

 1.7 mm in length, has the spines on the walking legs only partially de- 

 veloped. Because of the locality it probably belongs to the present spe- 

 cies.] 



measurements: Males, 2.6 to 4.4 mm; non-ovigerous females, 2.2 

 and 4.2 mm; ovigerous females, 3.7 and 3.9 mm. The type specimen, 

 of unspecified sex, was reported to measure 7 mm in length, 10 mm in 

 breadth. 



Color: All traces of color had disappeared in the specimens exam- 

 ined. 



Ecology: Dredged in 3-21 fathoms; taken from a shell bottom by 

 the Albatross and from substrates of sand, sandy mud, and coralline by 

 the Velero III. Depth of capture of the El Mogote specimen (Steinbeck 

 and Ricketts) was not specified. The species has not been found asso- 

 ciated with worm tubes. 



Ovigerous females have been collected in February. 



Relationships: The description of Poly onyx quadriungulatus ap- 

 plies to this species in all but a few particulars. From the small sample 

 of P. nitidus the following measurements were obtained: carapace 1.3 

 to 1.5 times as broad as long; carpus 1.3 to 1.6 times as long as wide; 

 length of palm in major cheliped 1.5 to 1.9 times that of fingers; in 

 minor cheliped, 1.1 to 1.3 times that of fingers. The spinules on the 

 posterior margin of the merus of the walking legs tend to be stronger 

 than in P. quadriungulatus. In addition to three posterodistal movable 

 spinules on the propodus and one on the middle or proximal third of 

 the posterior margin, a constant character in the California-western 

 Baja California species, P. nitidus has a fifth movable spinule located 



